Earth Science Today
Russ Colson
Minnesota State University Moorhead
Earth Science Today, Invertebrate fossils
1) Draw a picture of each sample.
2) For each fossil, write down one or two features you think are characteristic features (see
characteristic features that are listed for each phylum).
3) Identify the correct phyla for each using the provided sheets of fossil types.
Fossils:
Small picture and key feature
Phylum
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A3
.
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A4
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_
A7
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B5
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D6
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D7
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E1
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E2
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E4
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F1
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F3
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F5
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G4
Earth Science Today
Russ Colson
Minnesota State University Moorhead
Key to fossil groups
Some major invertebrate phyla of multi-cellular members of the animal kingdom are the following:
Porifera (these are the sponges)
often lack distinctive structures although spicules may be seen, may be spherical, or tubular.
Cnidaria (including jellyfish and corals)
corals are mostly colonial creatures with septated individual holes. Tabulate corals have layerlike tabulae,
rugose corals are horn shaped and may not be colonial.
Bryzoa (coral-like creatures)
are colonial, may be branching, encrusting, or fan-shaped. Small holes where individuals lived.
Brachiopoda (sea-shell like creatures)
2 shells, bilateral symmetry, opposing shells differ in size and/or shape.
Mollusca (including snails, sea-shells, octupus)
Pelecypods: 2 shells, bilateral assymetry, opposing shells often mirror images.
Gastropods: single coiled shell
Cephalopods: shell coiled or straight, if coiled it is usually in a single plane, suture lines
Arthropoda (includes insects, lobsters, and spiders)
Trilobites: bilateral symmetry, with head, thorax and pygidium.
Echinodermata (includes starfish)
pentameral symmetry, small plates, crinoid stems are distinctive "O's".
Pictures of various members of each phylum are available in the lab
and on my web page.